Plant growth method and composition using 2-chloro-ethyl phosphonic diamide

ABSTRACT

Plant growth regulating compound is 2-chloroethanephosphonic diamide of the formula: WHERE THE COMPOUND IS PREPARED BY THE REACTION OF AMMONIA WITH 2-CHLOROETHYLPHOSPHONYL DIHALIDE AND SUBSEQUENTLY PURIFIED TO REMOVE AMMONIUM HALIDE BY REACTION WITH A SECONDARY AMINE IN CHLOROFORM.

United States Patent l Randall et al.

I45! Jan.30, 1973 541 PLANT GROWTH METHOD AND COMPOSITION USINGZ-CHLORO- ETI-IYL PHOSPHONIC DIAMIDE [75] Inventors: David I. Randall;Robert Wynn, both of Easton, Pa.

[73] Assignee: GAF Corporation, New York, NY.

22 Filed: Dec. 23, 1969 [2i] Appl. No.: 887,752

[52] U.S. Cl. ..71/86, 260/551 P [51] Int. Cl. ..A0ln 9/36 [58] Field ofSearch ..7l/86, 87

[56] References Cited LFOIREIGNVPATENTS 0R APPLICATIONS 711,2'2'2'8/l9t38 Belgium ..7l/86 Primary Examinerlames 0. Thomas, Jr. AttorneySams on B Leavitt and Walter C. Ke'hm where the compound is prepared by thereaction of I ammonia with 2-chloroethylphosphonyl dihalide andsubsequently purified to remove ammonium halide by reaction with asecondary amine in chloroform.

6 Claims, N0 Drawings I PLANT GROWTH METHOD AND COMPOSITION USINGZ-CI-ILORO-ETIIYL PI-IOSPI-IONIC DIAMIDE BACKGROUND OF THE INVENTION 1.Field of the Invention This invention relates to 2-chloroethylphosphonicdiamide, useful as a plant growth regulator, and processes for itspreparation and purification.

2. Background of the Prior Art The art is aware that certainphosphorus-containing compounds are useful as plant growth regulators.One

of the most important phosphorus compounds of this type is2-chloroethylphosphonic acid which has found importance as a plantgrowth regulator, particularly in the treatment of pineapples, soy beansand other plants to control their rate of growth. The present inventionprovides a new phosphorus-containing compound useful as a plant growthregulator not known heretofore, which compound has utility in this areaequivalent to 2- chloroethylphosphonic acid. One of the primarycharacteristics of a product of this type is in .the presence of the2-chloroethyl group as this is important to the plant growth stimulatingactivity because it is believed that the action of the compound is dueto the fact that it is absorbed by the plant and releases ethylene, aknown plant regulator, in a form in which it can be used by the plant.

The art is aware of various substituted amides and diamides which havebeen prepared by reaction of an amine with a phosphonic acid dihalide.For example, in Izv. Akad. Nauk SSSR, Ser. Khim 1966 (18), pages1,365-70, there is disclosed the reaction of ClCH Cl-l,pcl withdiethylamine to provide the diethylamine diamide and ClCH OP=(NC I-IAlso, in Chemical Abstracts, Vol. 42, page 4,132, there is taught thereaction of aniline with chloroethanephosphonyl chloride to yield thedianiline derivative. However, none of these references show formationof the unsubstituted diamide or methods for its preparation. Moreover,none of the references show procedures for preparation of the compoundin substantially pure form.

SUMMARY OF THE'INVENTION economical process by which this'product may beproduced and a method for its purification.

Other objects and advantages of the present invention will becomeapparent as the description thereof proceeds.

In satisfaction of the foregoing objects and advantages, there isprovided by this invention a plant growth regulator of the followingformula:

Also provided is a process for preparation of this compound by thereaction of ammonia with a 2- chloroethylphosphonyl dihalide andsubsequent purification ofthe product to remove by-product ammoniumhalide by its reaction with a secondary amine in the presence ofchloroform whereby the by-product ammonium halide reacts with thesecondary amine to form gaseous ammonia which escapes to the atmosphereand'secondary ammonium halide (amine hydrochloride) which is soluble inchloroform.

DESCRIPTION OF PREFERRED EMBODIMENTS It has been found that theabove-identified 2- chloroethylphosphonic diamide has unique activity asa plant growth regulator and may be applied to plants' such aspineapples, soy beans, tomatoes, small grains and the'like to regulategrowth to thereby improve crop yields thereof. Thus, the compound may bestated to be a plant growth hormone as it operates to-increase yields ofthe products mentioned as well as others.

The compound of this invention is soluble in varying degrees in waterand so it can be applied to the plants in aqueous solutions composedwholly or partially of water; partial solutions include those formed ofwater and say acetone or methylethyl ketone. Any aqueous medium may beused provided that it is not toxic to the plant. Also, the compound maybe absorbed on solid carriers such as vermiculite, attaclay, talc andthe like for application in granular form. Dusts may also be used inwhich case theactive ingredient will be diluted with clays or otherpowders, for example pyrophyllite, diatom'aceous earth and attapulgite.

The compound of the invention can be applied to the plants at aconcentration of from one-half to 10 lbs/Acre or higher. A preferredrate of application ranges from 2-5 lbs/Acre. The compound needs only ito be applied to the plant in low volumes of water to achievesatisfactoryinitiation, and this is an important advantage of thisinvention. Whereas it is necessary to apply the known agents in largevolumes of water, on the order of 200-400 gallons/Acre, even up to 1,000gallons/Acre in the case of ethylene, to achieve initiation, it ispossible to apply the compound of this invention in far lower volumes ofwater to achieve satisfactory flower initiation. For example, thecompound of the present invention can be applied in 50 gallons of waterat the rate of l lb./Acre to achieve percent flower induction onpineapples of the Smooth Cayenne variety. The ability to apply the agentin a reduced volume of water is a great agronomic advantage because alarger acreage of plantation can be treated before recourse to a watersupply is necessary, smaller equipment can be used and costs can bereduced generally.

The compound of this invention may be prepared by the reaction of2'chloroethylphosphonyl dihalide of the following formula:

wherein X is halogen, preferably chlorine, but it may also bebromine,iodine or fluorine, with an excess of ammonia.

tion, in a preferred aspect, each of the reactants are mixed whilecontained in the solvent. Moreover, the ammonia reactant is preferablyutilized in excess to insure completeness of reaction.

The process is preferably conducted by charging each of the reactants toa portion of the solvent, and the solutions contacted at thetemperatures mentioned. in a preferred procedure, the solvent issaturated with ammonia gas and the starting'Z-chloroethyl compound isthen generally charged to the ammoniated solvent in a portion of thesolvent. A stream of the ammonia is then continuously passed into themixture.

As indicated the product of the invention is prepared by reacting anexcess of ammonia with a 2- chloroethylphosphonyl dihalide. Inthisreaction, there is formed the desired diamide product in good yieldbut there is also formed some ammonium halide (e.g. ammonium chloride)as an excess of ammonia is present to combine with the hydrogen halidereleased by formation of the product by reaction of the startingmaterial with ammonia. The crude mixture of diamide and ammoniumchloride or other halide may be used in the treatment of plants asdescribed hereinabove since the ammonium chloride is quite harmless toplants and animals'in the concentrations required and indeed may evenact as a fertilizer for furnishing nitrogen to the plants.

It is often desirable and sometimes necessary however to separate thediamide from the ammonium halide and the present invention provides asimple procedure for effecting this separation in a separate embodiment.According to this invention, the diamide and ammonium halide may beeasily separated by reacting the ammonium halide, while in admixturewith the diamide, with a secondary amine in chloroform. Suitablesecondary amines which may be employed include the dialkyl-amines(wherein the alkyl groups contain one to about seven carbon atoms),diarylamines (e.g. diphenylamine), diaralkylamines (e.g. dibenzylamine),dialkarylamines (e.g. ditolylamine), and mixtures thereof. A highlypreferred amine is diethylamine because of its ready availability.

in this reaction, the diamide/ammonium chloride mixture and about astoichiometric quantity of secondary amine are charged to the chloroformand gently refluxed until dissolution is complete. There is thus formeda secondary ammonium chloride (e.g. diethyl ammonium chloride withdiethylamine), which is soluble in chloroformand gaseous ammonia whichescapes from the solution. Oncooling the secondary ammoniurn chloride(amine hydrochloride) remains in solution and the product precipitatesas a crystalline solid and can be collected as by filtration. Thisresult is quite surprising as dehydrohalogenation of the carbon skeletonof the diamide would be expected to occur resulting in the formation ofvinylphosphonic diamide.

The following examples are provided to illustrate the compound andprocesses of the present invention.

EXAMPLE I 2-Chloroethylphosphonic Diamide There was charged to areaction flask 800 cc. dry chloroform. The solvent was saturated withdry ammonia gas at room temperature and whilecontinuing a slow stream ofammonia through the solution, there was added dropwise a solution of18.2 grams (0.1 mole) 2-chloroethanephosphonic dichloride in 100cc. drychloroform.

The product was collected in a sintered glass funnel and quickly placedin a vacuum desiccator where it was dried at room temperature. Themixture of product and ammonium chloride weighed 22.0 grams.

EXAMPLE ll I Purification of 2-Chloro ethylphosphonic Diamide Into anErlenmeyer flask there was charged 5.0 grams of the product from ExampleI, 3.7 grams diethylamine and 80 cc. of dry chloroform. While stirringon the magnetic stirrer, the mixture was gently refluxed untildissolution was complete. The solution was stored in the refrigeratorovernight and the product then collected and dried. Yield 1.5 grams, mp.lO9-ll2C.

Analysis Calcd. Found %Cl 24.91 24.57 am 19.65 20.08

EXAMPLE lIl 2-Chloroethylphosphonic Diamide: A charge of 500 cc. drybenzene was saturated with dry ammonia gas and while continuing a slowstream of ammonia through the solution at room temperature,

there was added dropwise a solution of 18.2 grams (0.1 mole)2-chloroethanephosphonic dichloride in 100 cc. dry benzene. The productwas collected on a sintered glass funnel and quickly placed in a vacuumdesiccator where it was dried to constant weight at room temperaitiatingor crop increasing amount of 2- chloroethanephosphonic diamide and acarrier therefor.

2. A composition as defined in claim 1 wherein said carrier is anaqueous medium.

3. A composition as defined in claim 1 wherein said carrier is a'solidmaterial.

4. Av method for regulating the growth of plants which comprisesapplying thereto an effective growthregulating amount of a compositionas defined in claim 6. A method for regulating the growth of plantswhich comprises thereto chloroethanephosphonic diamide at arate of about0.5 to 10 lbs. per acre of plants.

1. A plant growth regulating composition of matter comprising aneffective growth stimulating, flower initiating or crop increasingamount of 2-chloroethanephosphonic diamide and a carrier therefor.
 2. Acomposition as defined in claim 1 wherein said carrier is an aqueousmedium.
 3. A composition as defined in claim 1 wherein said carrier is asolid material.
 4. A method for regulating the growth of plants whichcomprises applying thereto an effective growth-regulating amount of acomposition as defined in claim
 1. 5. A method as defined in claim 4wherein said composition is applied at a rate of about 0.5 to 10 lbs. ofsaid 2-chloroethanephosphonic diamide per acre of plants.